A commonly used storage structure for multiple vehicles where space is limited, is a conventional parking garage in which vehicles can travel up and down in a structure along ramps, to and from parking bays within the structure. The volumetric efficiency of these storage structures is quite low, because of the space required for the ramps, for turning circles of vehicles, for opening vehicle doors, etc.
Many attempts have been made to improve on the volumetric efficiency of ramp parking garages, using active parking garages where vehicles are mechanically moved within a storage structure to park and retrieve vehicles, rather than driving them to and from parking bays. Some of these active parking garages have found acceptance among users, but generally, they are perceived as being too slow in storing and retrieving vehicles and they are generally not used to their full capacity—especially during peak parking and retrieval times.
In most existing active parking garages, vehicles need to be transferred between different structures, e.g. from a receiving platform to a bogey or a lift or into a parking bay and these transfers are time consuming. Active parking garages have been built where vehicles travel on platforms and do not require transfers, in the form of Ferris wheel or paternoster types of parking. However, these systems are inefficient and so slow that even though hundreds have been built particularly in Japan, they have never achieved fast parking. Some were built in the USA but today not one remains.
The present invention seeks to provide an active storage system that requires about half the space of a ramp parking garage of similar capacity. The invention further seeks to store and retrieve vehicles efficiently, preferably so efficiently that the active storage system will be used to capacity during peak parking time and peak retrieval time.